Chiang Kai-shek ranks as one of the most despised leaders of the 20th century. Famously derided as "Peanut" and "General Cash-My-Check," the leader of China's Nationalist government bedeviled the Allied war effort in World War II with his lackluster defense of his country. His corrupt and brutal regime squandered billions of dollars in American aid and drove the Chinese into the arms of the communists. He died in exile a deluded despot, relegated to a footnote in modern Chinese history. Or so the conventional story goes.

Now, however, Jay Taylor's new biography, "The Generalissimo: Chiang Kai-shek and the Struggle for Modern China," challenges the catechism on which generations of Americans have been weaned. Marshaling archival materials made newly available to researchers, including about four decades' worth of Chiang's daily diaries and documents from the Soviet era, it torpedoes many of that catechism's cherished tenets. This is an important, controversial book.

Taylor, who was a U.S. Foreign Service officer in Hong Kong during the Cultural Revolution, argues that, far from being incompetent, Chiang was a farsighted, disciplined and canny strategist who repeatedly predicted major geopolitical events and made the most of the weak hand he was usually dealt by allies and enemies. His five decades of participation, at the highest levels, in world-changing events may be unsurpassed in the 20th century. For all his flaws as a political leader, Chiang laid the foundation not only for Taiwan's prosperity, but also for its transformation into the only democracy in the Chinese-speaking world, and one of the few in Asia.

"The Generalissimo" is especially timely appearing as it does during a period of flux and promise in the delicate dance between Taiwan and China. A new closeness is apparently taking hold: trade agreements are being signed, direct flights are being established and Chinese tourists are flocking to the island. There's even talk of a peace treaty. So the book naturally raises the question: Whose vision of China's future is really winning? Is it Chiang's dream of a more free-wheeling nation, or the image of a revolutionary utopia championed by his communist nemesis, Mao Zedong?

Taylor reveals intriguing details, such as Chiang's decades-long secret communications, after his 1949 defeat, with Mao's No. 2, Zhou Enlai. He describes Mao receiving instructions and trunks full of Mexican silver dollars from Soviet leader Joseph Stalin -- without which, Taylor argues, the fabled Long March probably would have been impossible. He debunks the view that Chiang's entire military record was one of abject failure and sheds fresh light on Chiang's ties to the United States during the Cold War conflicts in Korea and Vietnam. Chiang strenuously warned President Lyndon B. Johnson against being drawn into the latter war. And Taylor adds depth and detail to the saga of the 1970s U.S.-China détente and Washington's eventual recognition of Beijing, describing how Chiang concealed his bitter loathing of President Richard Nixon.

Chiang emerges as a flesh-and-blood man rather than the buffoonish cardboard-cutout figure he has generally been portrayed as. China's nationalist leader is revealed as a tormented soul, as prone to bursting into tears as into angry tirades, who through force of will conquered his own demons to -- as he saw it -- lead his people out of colonial oppression and moral decay to forge a strong, unified nation.

Born the son of a village salt merchant and raised by his widowed mother, Chiang Kai-shek rose to rule the world's most populous country. After revered revolutionary Sun Yat-sen died in 1925, Chiang seized power. In 1927, he launched a bloody purge of the Chinese Communist Party, which had been cooperating with Sun's Nationalist Party, touching off decades of civil conflict. Soon after, he married Sun's sister-in-law, Mayling Soong, the youngest daughter of a wealthy and powerful Shanghai family and a formidable figure in her own right.

In the 1930s, he tried to hold Japan's armies at bay while battling the communists -- until 1937, when full-scale war erupted with Japan, and he joined forces with Mao. After Pearl Harbor -- Chiang had long predicted that Japan would target the United States -- he joined the Allies. As World War II ended, he resumed fighting the communists. After his defeat, he retreated to the island of Taiwan, then called Formosa.